When people become lost in wilderness areas, rescue workers and emergency responders are often tasked with searching an area of difficult terrain, and possibly unfamiliar surroundings. Often, search vehicles such as helicopters, airplanes, and off-road motor vehicles may be utilized to cover more search area than would be possible by humans searching on foot. With the development of unmanned aerial vehicles (UAVs), commonly referred to as “drones”, additional resources can be applied to rescue efforts for lost individuals. One difficulty when searching on foot, or when using both manned and unmanned vehicles, is they generally depend on a visual sighting of the missing party.